Bump sphinx from 8.1.3 to 8.2.3 (spack#428)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 8.1.3 to 8.2.3.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v8.1.3...v8.2.3)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -1,6 +1,6 @@
 # These dependencies should be installed using pip in order
 # to build the documentation.
-Sphinx==8.1.3
+Sphinx==8.2.3
 sphinxcontrib-programoutput==0.18
 sphinx-rtd-theme==3.0.2
 sphinx-copybutton==0.5.2